Chevrolet 70 1969 Series, Shop Manual

Page: 432 / 913

T R A N SM ISSIO N S A N D CLUTCHES 70-27
Figure 11— Using Large End of Tool
Clutch master cylinder is accessible under
the hood on conventional cab models, through ac­
cess door on T Models, and under the dash on T
Models 80.
Plain end of bleeder hose can be slipped over
end of bleeder valve.
Clutch system may be bled either manually or
with pressure bleeding equipment.
PRESSURE B L E E D IN G
1. Make sure fluid level in fluid supply pres­
sure tank is up to pet cock above outlet and that
tank is charged with 25 to 30 psi air pressure.
2. Clean dirt from around master cylinder
cover or cap. On units having reservoir cover in­
stead of cap, remove standard cover and install
special cover (J-8554). Connect pressure tank hose
to filler cap or special cover opening. Bleed air
from hose before tightening connection. Open
valves at both ends of hose.
C A U T IO N : On tilt cab models 80 with master
cylinder mounted inside of cab, use extreme care
not to spill fluid on clutch or brake pedal pads. If
fluid spills on pedal pads, it must be washed off so
that pads will not be slippery.
3. Slip end of bleeder drain hose over bleed
valve at slave cylinder (fig. 12) and place the other
end in a glass jar containing enough hydraulic fluid
to cover end of hose. Open bleeder valve with
wrench and observe flow of fluid from hose. Close
bleeder valve as soon as bubbles stop and fluid
flows in a solid stream.
M A N U A L B L E E D IN G
Manual bleeding is the same as pressure bleed­
ing, except that the hydraulic fluid is forced through
the line by pumping the clutch pedal. Fluid in m as­
ter cylinder must be replenished after bleeding.
Clutch pedal should be pumped up and down slowly,
1 Cylinder Assy.
2 Bleeder Valve
3 Return Spring Bracket
4 Return Spring
5 Release Fork
6 Cylinder Push Rod
7 Wedge
8 Adjustment Nut
9 Lock Nut
10 Hydraulic Line Assy.
T-2980
Figure 12— Slave Cylinder Installed tTypicalI
and should be on downstroke as bleeder valve is
closed.
CLUTCH PEDAL AN D SHAFT
REPLACEMENT
(ALL CONVENTIONAL CAB MODELS)
Instructions for replacing clutch pedal and
1 Push Rod Boot
2 Cylinder Housing
3 Cover
4 Cover Screw
5 Piston Return Spring
6 Primary Cup
7 Piston
8 Secondary Cup
9 Snap Ring
Figure 13— Clutch Master Cylinder (Typical for
Conv. Cab and Tilt Cab Models— 70)
CHEVROLET- SERIES 7 0 -8 0 H EAVY
D U T Y T R U C K S H O P M A N U A L